[Densitometric determination of nicotinamide in multivitamin preparations after thin layer chromatographic separation].

Nicotinamide was determined in 7 multivitamin preparations after TLC by remission measurement at 262 nm. Advantages of the method as compared with methods described so far are that scratching off from the plate and eluating as well as spray reagents are not necessary, in particular the use of the highly dangerous cyanogen bromide can be dispensed with. On silica gel 60 F 254 a separation of nicotinamide was possible with acetone-chloroform-n-butanol-concentrated ammonia solution 30:30:40:5 and 30:30:40:2, respectively. Densitometric determination is disturbed neither by the water-soluble vitamins B1, B2, B6, B12, C, dexpanthenol, p-aminobenzoic acid nor by caffeine, procaine and pharmaceutical auxiliary substances. The fat-soluble vitamins A, D2 and E were removed, if necessary, from the test solution by petrolether extraction. The method has proved a success in several years' use for pharmaceutical expertises and control investigations.